1. Field of the Invention
The present invention relates generally to apparatus and methods for the percutaneous closure of body lumens. More particularly, the present invention relates to apparatus and methods for the percutaneous closure of arterial and venous puncture sites, which are usually accessible only through a tissue tract.
A number of diagnostic and interventional vascular procedures are now performed transluminally, where a catheter is introduced to the vascular system at a convenient access location and guided through the vascular system to a target location using established techniques. Such procedures require vascular access which is usually established using the well known Seldinger technique, as described, for example, in William Grossman's "Cardiac Catheterization and Angiography," 3rd Ed., Lea and Febiger, Philadelphia, 1986, incorporated herein by reference.
When vascular access is no longer required, the introducer sheath must be removed and bleeding at the puncture site stopped. One common approach for providing hemostasis (the cessation of bleeding) is to apply external force near and upstream from the puncture site, typically by manual or "digital" compression. This approach suffers from a number of disadvantages. It is time-consuming, frequently requiring one-half hour or more of compression before hemostasis is assured. Additionally, such compression techniques require clot formulation and therefore cannot begin until anticoagulants used in vascular therapy procedures (such as for heart attacks, stent deployment, non-optimal PTCA results, and the like) are allowed to wear off. This can take up to two to four hours, thereby increasing the time required under the compression technique. The compression procedure is further uncomfortable for the patient and frequently requires administering analgesics to be tolerable. Moreover, the application of excessive pressure can at times totally occlude the underlying blood vessel, resulting in ischemia and/or thrombosis. Following manual compression the patient is required to remain recumbent for at least four and at times longer than 12 hours under close observation to assure continued hemostasis. During this time renewed bleeding may occur resulting in bleeding through the tract, hematoma and/or pseudo aneurysm formation as well as arteriovenous fistula formation. These complications may require blood transfusion and/or surgical intervention. The incidence of these complications increases when the sheath size is increased and when the patient is anticoagulated. It is clear that the standard technique for arterial closure can be risky, and is expensive and onerous to the patient. While the risk of such conditions can be reduced by using highly trained individuals, such use is both expensive and inefficient.
To overcome the problems associated with manual compression, the use of bioabsorbable fasteners to stop bleeding has been proposed by several groups. Generally, these approaches rely on the placement of a thrombogenic and bioabsorbable material, such as collagen, at the superficial arterial wall over the puncture site. While potentially effective, this approach suffers from a number of problems. It can be difficult to properly locate the interface of the overlying tissue and the adventitial surface of the blood vessel, and locating the fastener too far from that surface can result in failure to provide hemostasis and subsequent hematoma and/or pseudo aneurysm formation. Conversely, if the fastener intrudes into the arterial lumen, intravascular clots and/or collagen pieces with thrombus attached can form and embolies downstream causing vascular occlusion. Also, thrombus formation on the surface of a fastener protruding into the lumen can cause a stenosis which can obstruct normal blood flow. Other possible complications include infection as well as adverse reactions to the collagen implant.
A more effective approach for vascular closure has been proposed in U.S. Pat. No. 5,417,699 and in co-pending application Ser. Nos. 08/148,809 and PCT/US93/11864. A suture applying device is introduced through the tissue tract with a distal end of the device located at the vascular punctures. One or more needles in the device are then used to draw suture through the blood vessel wall on opposite sides of the punctures, and the suture is secured directly over the adventitial surface of the blood vessel wall to provide highly reliable closure.
While a significant improvement over the use of manual pressure, clamps, and collagen plugs, certain design criteria have been found to be important to successful suturing to achieve vascular closure. For example, it is important that the needles be properly directed through the blood vessel wall so that the suture is well anchored in tissue to provide for tight closure. It is also important that needle deployment within the suturing device be controlled to prevent accidental deployment before the device has been properly introduced to the puncture site in a blood vessel. It is of further importance that the vascular suturing device be able to be introduced to blood vessels without imposing significant or undue trauma to the patient. In particular, it is particularly desirable to close the vessel in a relatively short amount of time and without imposing excessive injury to the tissue tract leading to the vessel.
For these reasons, it would be desirable to provide apparatus, systems, and methods for suturing vascular punctures which meet all or some of the criteria discussed above.
2. Description of the Background Art
Devices capable of delivering pairs of needles to various tissue locations are described in the following patents and patent applications: U.S. Pat. Nos. 4,493,323 and 659,422; European patent application 140 557; and U.S.S.R. patent applications 1174-036-A and 1093-329-A. A suturing device that carries a pair of needles having suture therebetween is described in a brochure entitled "Innovation through Progress," REMA-MEDIZINTECHNIK, Gmbh, January, 1992. A suturing device having a partially flared cylindrical core for delivering needles to suture anastomoses is described in U.S. Pat. No. 4,553,543. Other suturing and ligating devices are described in U.S. Pat. Nos. 5,171,251; 5,160,339; 4,317,445; 4,161,951; 3,665,926; 2,959,172; 2,646,045; and 312,408. Devices for sealing percutaneous vascular punctures using various plugs and fastener structures are described in U.S. Pat. Nos. 5,222,974; 5,192,302; 5,061,274; 5,021,059; 4,929,246; 4,890,612; 4,852,568; 4,744,364; 4,587,969; and 3,939,820. Collagen fastener sealing devices are under commercial development by Datascope Corp., Montvale, N.J., and Kensey Nash Corporation, Exton, Pa. Copending application Ser. No. 08/148,809, describes a vascular suturing device having a needle guide with a constant peripheral dimension.